Amplifier



NOV. 19, 1935. N, RAMLAU 2,021,638

AMPLIFIER Filed Sept. 8, 1952 INVENTOR P. N: RAMLAU /f WW ATTORNEY desired amplitude.

Patented Nov. 19, 1935 PATENT OFFICE AMPLIFIER Paul N. Ramlau, Leningrad, Union of Soviet Socialist Republics, assignor to Gosudarstvennoje Usesojuznoje Objedinenje Elektroslabotochnoj Promyshlennosti, Leningrad, Union of Soviet Socialist Republics, an organization of the Union of Soviet Socialist Republics Application September 8, 1932, Serial No. 632,238.

In Union of Soviet Socialist Republics December 8, 1930 3 Claims. (Cl. 179-170) In order to transmit high frequency oscillations over long distance wires, it is necessary to use thermionic amplifiers to bring the signal, which is attenuated during transmission, to the In order to reduce the amount of apparatus, it is desirable that the repeating amplifiers be of the two-way type, that is, the amplifiers must amplify the signals travelling from one line into the other line, as well as the signals that proceed from the last line in the direction of the first line. It has been customary to use for this purpose two amplifiers which are included in the diagonals of Wheatstone bridges in order to avoid regeneration in the amplifiers and circuits. If the bridges are not exactly balanced, that is, are not tuned, there will be disturbances in the lines in the form of noises and whistling sounds.

The herein proposed high frequency amplifying repeater may, according to the invention, be inserted into the line without bridges and yet eliminates entirely any possibility of regeneration.

The circuit arrangement and mode of operating an amplifier or repeater constructed in accordance with my invention will now be set forth. In describing the repeater, reference will be had to the drawing, wherein Figures 1 to 3 inclusive show various preferred forms which the repeater may take. The signals may come in on line I, be amplified in the amplifying repeater Ill and impressed by way of coupling capacity C1 on to the transformer coupled with the outgoing line 2. The signals coming in from line 2 may be amplified in tube II and impressed therefrom by way of condenser C2 on to the transformer coupled with line I, which, in this case, is the outgoing line. The plates P and P1 of the tubes II) and II included in the lines I and 2 are supplied with above audible alternating current from source T so that when the plate current of one tube is positive the plate current of the other tube will be negative. On account of such an arrangement the high frequency coming through the line I is divided into a number of separate impulses amplified by the tube IIl. These high frequency impulses are transmitted to the line 2 by way of a condenser C1. During the transmission of high frequency impulses from I to 2 the plate of the second tube l I will always be under a negof a two-way high frequency amplifier.

ative voltage, which precludes the possibility of any influence of 2 on 1 by way of this tube I I.

The frequency of the plate voltage must be 4 lower than the radio frequency in the lines I and 2 but above audio frequency, i. e., it must be sufiiciently high for convenient filtration subsequent to its detection in the receiver.

The choke coils L1 and L2 are to protect the source of the plate voltage against high frequency currents. Each line may contain several tubes, connected either parallel or according to a pushpull system.

Figure 2 illustrates a push-pull arrangement The amplifier may also consist of screen grid tubes. In this case the plate may be supplied with direct current and an alternating voltage applied to the screening grids as shown on diagram 3.

Having thus described my invention and the operation thereof, what I claim is:

1. An amplifying two-way repeater to be interposed between two lines, each of which may serve alternately as incoming and outgoing lines without producing reaction between the signals in said lines, including, pairs of thermionic amplifying repeaters, each repeater having anode, cathode and control grid electrodes, a circuit connecting the control grids of one of said pairs of tubes in push-pull relation to one of said lines only, a circuit connecting the control grids of another pair of said tubes in push-pullrelation to the other of said lines only, capacities coupling the anodes of said first named pair of tubes to said other of said lines, capacities coupling the anodes of said other pair of tubes to said one of said lines, and means for alternately applying operative energizing potentials to the anodes of the tubes in said pairs.

2. A device as recited in claim 1 in which. said means for applying energizing potentials to the anodes of said tubes includes a transformer having each terminal of its secondary winding coupled to the anodes in a different pair of said tubes and its electrical center connected to the cathode of all of said tubes, and its primary winding energized by alternating current of a frequency above audible frequency.

3. An amplifying two-way repeater to be interposed between two lines each of which may serve alternately as incoming and outgoing lines without producing reaction between audible signals in said lines including, a pair of thermionic tubes each having an anode, a cathode and a control grid, a coupling between the control grid and cathode of one of said tubes and one of said lines, a coupling between the control grid and cathode of the other of said tubes and the remaining line, a condenser coupling the anode of said first named tube to said last named line, a condenser coupling the anode of said last named tube to said one of said lines, a transformer having a secondary winding and a primary winding which may be coupled to a source of oscillations of a frequency above audibility, a connection between one terminal of the secondary winding of said transformer and the anode of one of said tubes, a connection between the other terminal of the secondary winding of said transformer and the anode of the other of said tubes, and a connection between a point on said secondary winding and the cathodes of both of said tubes.

PAUL N. RAMLAU. 

